The present invention relates to a locking structure for a ball valve and, more specifically, to a locking device that will be able to effectively accommodate with a modest change a number of different kinds of locking pins which are available from manufacturers. Further, the present invention will provide a locking structure which is less costly to manufacture and will more reliably operate to protect the ball valve from unauthorized operation either in the open or closed positions.
In the water and gas distribution fields, it has long been necessary to provide locking devices for valves to control the supply of water and gas to consumers, for safety reasons, during assembly of a system and for a number of other reasons. Chief among these are the prevention of unauthorized taking of the fluid being supplied and safety reasons in case of a requirement for cutoff of the fluid being supplied in the event of leakage in a distribution system. One common kind of locking system involves the use of a locking post that extends externally of the valve body generally perpendicular to the valve stem and is provided with through apertures which cooperate with an aperture provided in the valve stem handle so that an operator can prevent rotation of the valve stem by inserting a locking member through the aligned apertures of the locking post and valve stem handle. A separate locking device is then typically required to secure the locking member in place. These and other types of arrangements are relatively expensive to manufacture. In addition, such systems are subject to hand operation with relative ease and thus have not satisfied the primary reasons for their incorporation into a valve structure. Furthermore, in many instances, locking in the open position is not possible without additional devices.
The present invention avoids the difficulties of the locking devices of the prior art and provides a very reliable and less expensive locking system and one which can be easily modified to accommodate different locking pins which are available from manufacturers of such devices. Further, the locking system of this invention will be less subject to successful tampering than the prior art structures now available.
In a preferred embodiment, the valve body is provided with a locking post formed with the valve body to extend externally of the body generally parallel to the direction that the valve stem extends. The locking post and valve stem are provided or shaped with surfaces that enable the reception of a locking pin which can be inserted into a locking position by a user manually or with the aid of a tool supplied by the manufacturer of the locking pin or device. The valve mechanism in the present invention will be tamper resistant in use in view of the absence of sufficient leverage to turn the valve stem by hand.
The foregoing and other advantages will become apparent as consideration is given to the following description and accompanying drawings, in which: